Ailina Tsarnaeva, 23 years old, called the victim, also 23, on Monday and threatened her with a bomb, according to the New York Police Department. “I have people who can go up there and put a bomb on you,” she allegedly told the woman, according to a law-enforcement official.

The victim reported the incident to police, and Ms. Tsarnaeva turned herself in at the 30th Precinct in Harlem at 2:30 p.m. on Wednesday, police said.

Ms. Tsarnaeva was charged with aggravated harassment and was given a summons to appear in court on Sept. 30.

Police said Ms. Tsarnaeva is the sister of Dzhokhar Tsarnaev, who is charged with the bombing at the marathon in 2013, killing three people and injuring more than 250 others. He has pleaded not guilty.

Mr. Tsarnaev’s brother, Tamerlan Tsarnaev, died in a confrontation with police shortly after the marathon bombings.